Chesapeake Times, Vol 12 | Oct 2023
Although the SEGY file format is getting closer to celebrating its 50th birthday, originally developed in the mid-70s, our industry still considers these the standard for storing sub-bottom profiler data. We have come a long way from its original specifications for magnetic tapes and SonarWiz has required multiple updates over the years to customize the exports coming out of the program.
With the recent introduction of Topographic corrections and tidal corrections in the 7.09 release, we also needed to give a face lift to the CSF to SEGY export dialog as previous versions didn’t contain many customization options. Since most software packages can both read and write SEGY files, there is an endless number of combinations of byte location configurations and now SonarWiz can fully support any of these coming in or out of the program!
First and foremost, you will need to determine whether your exported data will have the Topographic correction applied as this will adjust many of the options available. We wrote about these changes in the last newsletter, the article can be found here (please link: https://chesapeaketech.com/sonarwiz-sub-bottom-data-topographic-correction)! The left-hand column, which lists the possible data fields for export, will change depending on the checkbox below:
For example, a program like Kingdom Suite requires all the data fields from imported SEGY files to be stored in time and not depth. This limits the use of some of the common byte locations and is best paired with the new Topographic corrections option.
A well populated EBCDIC header might not seem as important as maintaining vertical values but I myself have spent hours with customers data trying to identify proper field locations and trial and error. When using the CSF to SEGY tool SonarWiz will add a default header, but a custom one can be added to provide additional information. Did you know that you can add macros to lines in the header that SonarWiz will automatically populate with information from the CSF file? Some of the supported options are $FILENAME$ and $SAMPLESPERTRACE$, we have a document available on our website with the full list.
It is nearly impossible for a program to export a “standard” version of a SEGY file which still includes all the processing done in SonarWiz, so our goal was to give the user complete customization. Our staff has years of experiencing working with SEGY file and if you ever have any questions, we are happy to field them.